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<pre><span class="sourceLineNo">001</span>/**<a name="line.1"></a>
<span class="sourceLineNo">002</span> * Copyright (c) 2004-2011 QOS.ch<a name="line.2"></a>
<span class="sourceLineNo">003</span> * All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * Permission is hereby granted, free  of charge, to any person obtaining<a name="line.5"></a>
<span class="sourceLineNo">006</span> * a  copy  of this  software  and  associated  documentation files  (the<a name="line.6"></a>
<span class="sourceLineNo">007</span> * "Software"), to  deal in  the Software without  restriction, including<a name="line.7"></a>
<span class="sourceLineNo">008</span> * without limitation  the rights to  use, copy, modify,  merge, publish,<a name="line.8"></a>
<span class="sourceLineNo">009</span> * distribute,  sublicense, and/or sell  copies of  the Software,  and to<a name="line.9"></a>
<span class="sourceLineNo">010</span> * permit persons to whom the Software  is furnished to do so, subject to<a name="line.10"></a>
<span class="sourceLineNo">011</span> * the following conditions:<a name="line.11"></a>
<span class="sourceLineNo">012</span> *<a name="line.12"></a>
<span class="sourceLineNo">013</span> * The  above  copyright  notice  and  this permission  notice  shall  be<a name="line.13"></a>
<span class="sourceLineNo">014</span> * included in all copies or substantial portions of the Software.<a name="line.14"></a>
<span class="sourceLineNo">015</span> *<a name="line.15"></a>
<span class="sourceLineNo">016</span> * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,<a name="line.16"></a>
<span class="sourceLineNo">017</span> * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF<a name="line.17"></a>
<span class="sourceLineNo">018</span> * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND<a name="line.18"></a>
<span class="sourceLineNo">019</span> * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE<a name="line.19"></a>
<span class="sourceLineNo">020</span> * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION<a name="line.20"></a>
<span class="sourceLineNo">021</span> * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION<a name="line.21"></a>
<span class="sourceLineNo">022</span> * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.<a name="line.22"></a>
<span class="sourceLineNo">023</span> *<a name="line.23"></a>
<span class="sourceLineNo">024</span> */<a name="line.24"></a>
<span class="sourceLineNo">025</span>package org.slf4j.helpers;<a name="line.25"></a>
<span class="sourceLineNo">026</span><a name="line.26"></a>
<span class="sourceLineNo">027</span>import junit.framework.AssertionFailedError;<a name="line.27"></a>
<span class="sourceLineNo">028</span><a name="line.28"></a>
<span class="sourceLineNo">029</span>/**<a name="line.29"></a>
<span class="sourceLineNo">030</span> * BogoPerf is used to check that the time required to perform a certain<a name="line.30"></a>
<span class="sourceLineNo">031</span> * operation does not deteriorate over time. BogoPerf adjusts to the CPU speed<a name="line.31"></a>
<span class="sourceLineNo">032</span> * and capabilities of the host.<a name="line.32"></a>
<span class="sourceLineNo">033</span> * <a name="line.33"></a>
<span class="sourceLineNo">034</span> * @author Ceki G&amp;uuml;lc&amp;uuml;<a name="line.34"></a>
<span class="sourceLineNo">035</span> * <a name="line.35"></a>
<span class="sourceLineNo">036</span> */<a name="line.36"></a>
<span class="sourceLineNo">037</span>public class BogoPerf {<a name="line.37"></a>
<span class="sourceLineNo">038</span><a name="line.38"></a>
<span class="sourceLineNo">039</span>    private static long NANOS_IN_ONE_SECOND = 1000 * 1000 * 1000;<a name="line.39"></a>
<span class="sourceLineNo">040</span>    private static int INITIAL_N = 1000;<a name="line.40"></a>
<span class="sourceLineNo">041</span>    private static int LAST_N = 100;<a name="line.41"></a>
<span class="sourceLineNo">042</span>    private static int SLACK_FACTOR = 3;<a name="line.42"></a>
<span class="sourceLineNo">043</span><a name="line.43"></a>
<span class="sourceLineNo">044</span>    static {<a name="line.44"></a>
<span class="sourceLineNo">045</span>        // let the JIT warm up<a name="line.45"></a>
<span class="sourceLineNo">046</span>        computeBogoIPS(INITIAL_N);<a name="line.46"></a>
<span class="sourceLineNo">047</span>        double bogo_ips = computeBogoIPS(INITIAL_N);<a name="line.47"></a>
<span class="sourceLineNo">048</span>        System.out.println("Host runs at " + bogo_ips + " BIPS");<a name="line.48"></a>
<span class="sourceLineNo">049</span>    }<a name="line.49"></a>
<span class="sourceLineNo">050</span><a name="line.50"></a>
<span class="sourceLineNo">051</span>    /**<a name="line.51"></a>
<span class="sourceLineNo">052</span>     * Compute bogoInstructions per second<a name="line.52"></a>
<span class="sourceLineNo">053</span>     * &lt;p&gt;<a name="line.53"></a>
<span class="sourceLineNo">054</span>     * on a 3.2 Ghz Pentium D CPU (around 2007), we obtain about 9'000 bogoIPS.<a name="line.54"></a>
<span class="sourceLineNo">055</span>     * <a name="line.55"></a>
<span class="sourceLineNo">056</span>     * @param N<a name="line.56"></a>
<span class="sourceLineNo">057</span>     *                number of bogoInstructions to average over in order to<a name="line.57"></a>
<span class="sourceLineNo">058</span>     *                compute the result<a name="line.58"></a>
<span class="sourceLineNo">059</span>     * @return bogo Instructions Per Second<a name="line.59"></a>
<span class="sourceLineNo">060</span>     */<a name="line.60"></a>
<span class="sourceLineNo">061</span>    private static double computeBogoIPS(int N) {<a name="line.61"></a>
<span class="sourceLineNo">062</span>        long begin = System.nanoTime();<a name="line.62"></a>
<span class="sourceLineNo">063</span><a name="line.63"></a>
<span class="sourceLineNo">064</span>        for (int i = 0; i &lt; N; i++) {<a name="line.64"></a>
<span class="sourceLineNo">065</span>            bogoInstruction();<a name="line.65"></a>
<span class="sourceLineNo">066</span>        }<a name="line.66"></a>
<span class="sourceLineNo">067</span>        long end = System.nanoTime();<a name="line.67"></a>
<span class="sourceLineNo">068</span><a name="line.68"></a>
<span class="sourceLineNo">069</span>        // duration<a name="line.69"></a>
<span class="sourceLineNo">070</span>        double D = end - begin;<a name="line.70"></a>
<span class="sourceLineNo">071</span>        // average duration per instruction<a name="line.71"></a>
<span class="sourceLineNo">072</span>        double avgDPIS = D / N;<a name="line.72"></a>
<span class="sourceLineNo">073</span>        // System.out.println(D + " nanos for " + N + " instructions");<a name="line.73"></a>
<span class="sourceLineNo">074</span>        // System.out.println(avgD + " nanos per instruction");<a name="line.74"></a>
<span class="sourceLineNo">075</span><a name="line.75"></a>
<span class="sourceLineNo">076</span>        double bogoIPS = NANOS_IN_ONE_SECOND / avgDPIS;<a name="line.76"></a>
<span class="sourceLineNo">077</span>        // System.out.println(bogoIPS + " bogoIPS");<a name="line.77"></a>
<span class="sourceLineNo">078</span><a name="line.78"></a>
<span class="sourceLineNo">079</span>        return bogoIPS;<a name="line.79"></a>
<span class="sourceLineNo">080</span>    }<a name="line.80"></a>
<span class="sourceLineNo">081</span><a name="line.81"></a>
<span class="sourceLineNo">082</span>    private static void bogoInstruction() {<a name="line.82"></a>
<span class="sourceLineNo">083</span>        // use our own random number generator, independent of the host JDK<a name="line.83"></a>
<span class="sourceLineNo">084</span>        MyRandom myRandom = new MyRandom(100);<a name="line.84"></a>
<span class="sourceLineNo">085</span>        int len = 150;<a name="line.85"></a>
<span class="sourceLineNo">086</span>        int[] intArray = new int[len];<a name="line.86"></a>
<span class="sourceLineNo">087</span>        for (int i = 0; i &lt; len; i++) {<a name="line.87"></a>
<span class="sourceLineNo">088</span>            intArray[i] = myRandom.nextInt();<a name="line.88"></a>
<span class="sourceLineNo">089</span>        }<a name="line.89"></a>
<span class="sourceLineNo">090</span>        // use our own sort algorithm, independent of the host JDK<a name="line.90"></a>
<span class="sourceLineNo">091</span>        BubbleSort.sort(intArray);<a name="line.91"></a>
<span class="sourceLineNo">092</span>    }<a name="line.92"></a>
<span class="sourceLineNo">093</span><a name="line.93"></a>
<span class="sourceLineNo">094</span>    /**<a name="line.94"></a>
<span class="sourceLineNo">095</span>     * Computed the BogoIPS for this host CPU.<a name="line.95"></a>
<span class="sourceLineNo">096</span>     * <a name="line.96"></a>
<span class="sourceLineNo">097</span>     * @return<a name="line.97"></a>
<span class="sourceLineNo">098</span>     */<a name="line.98"></a>
<span class="sourceLineNo">099</span>    public static double currentBIPS() {<a name="line.99"></a>
<span class="sourceLineNo">100</span>        return computeBogoIPS(LAST_N);<a name="line.100"></a>
<span class="sourceLineNo">101</span>    }<a name="line.101"></a>
<span class="sourceLineNo">102</span><a name="line.102"></a>
<span class="sourceLineNo">103</span>    static double min(double a, double b) {<a name="line.103"></a>
<span class="sourceLineNo">104</span>        return (a &lt;= b) ? a : b;<a name="line.104"></a>
<span class="sourceLineNo">105</span>    }<a name="line.105"></a>
<span class="sourceLineNo">106</span><a name="line.106"></a>
<span class="sourceLineNo">107</span>    /**<a name="line.107"></a>
<span class="sourceLineNo">108</span>     * Assertion used for values that &lt;b&gt;decrease&lt;/b&gt; with faster CPUs, typically<a name="line.108"></a>
<span class="sourceLineNo">109</span>     * the time (duration) needed to perform a task.<a name="line.109"></a>
<span class="sourceLineNo">110</span>     * <a name="line.110"></a>
<span class="sourceLineNo">111</span>     * @param currentDuration<a name="line.111"></a>
<span class="sourceLineNo">112</span>     * @param referenceDuration<a name="line.112"></a>
<span class="sourceLineNo">113</span>     * @param referenceBIPS<a name="line.113"></a>
<span class="sourceLineNo">114</span>     * @throws AssertionFailedError<a name="line.114"></a>
<span class="sourceLineNo">115</span>     */<a name="line.115"></a>
<span class="sourceLineNo">116</span>    public static void assertDuration(double currentDuration, long referenceDuration, double referenceBIPS) throws AssertionFailedError {<a name="line.116"></a>
<span class="sourceLineNo">117</span>        double ajustedDuration = adjustExpectedDuration(referenceDuration, referenceBIPS);<a name="line.117"></a>
<span class="sourceLineNo">118</span>        if (currentDuration &gt; ajustedDuration * SLACK_FACTOR) {<a name="line.118"></a>
<span class="sourceLineNo">119</span>            throw new AssertionFailedError("current duration " + currentDuration + " exceeded expected " + ajustedDuration + " (adjusted reference), "<a name="line.119"></a>
<span class="sourceLineNo">120</span>                            + referenceDuration + " (raw reference)");<a name="line.120"></a>
<span class="sourceLineNo">121</span>        }<a name="line.121"></a>
<span class="sourceLineNo">122</span>    }<a name="line.122"></a>
<span class="sourceLineNo">123</span><a name="line.123"></a>
<span class="sourceLineNo">124</span>    /**<a name="line.124"></a>
<span class="sourceLineNo">125</span>     * Assertion used for values that &lt;b&gt;increase&lt;b&gt; with faster CPUs, typically<a name="line.125"></a>
<span class="sourceLineNo">126</span>     * the number of operations accomplished per unit of time.<a name="line.126"></a>
<span class="sourceLineNo">127</span>     * <a name="line.127"></a>
<span class="sourceLineNo">128</span>     * @param currentPerformance<a name="line.128"></a>
<span class="sourceLineNo">129</span>     * @param referencePerformance<a name="line.129"></a>
<span class="sourceLineNo">130</span>     * @param referenceBIPS<a name="line.130"></a>
<span class="sourceLineNo">131</span>     * @throws AssertionFailedError<a name="line.131"></a>
<span class="sourceLineNo">132</span>     */<a name="line.132"></a>
<span class="sourceLineNo">133</span>    public static void assertPerformance(double currentPerformance, long referencePerformance, double referenceBIPS) throws AssertionFailedError {<a name="line.133"></a>
<span class="sourceLineNo">134</span>        double ajustedPerf = adjustExpectedPerformance(referencePerformance, referenceBIPS);<a name="line.134"></a>
<span class="sourceLineNo">135</span>        if (currentPerformance * SLACK_FACTOR &lt; ajustedPerf) {<a name="line.135"></a>
<span class="sourceLineNo">136</span>            throw new AssertionFailedError(currentPerformance + " below expected " + ajustedPerf + " (adjusted), " + referencePerformance + " (raw)");<a name="line.136"></a>
<span class="sourceLineNo">137</span>        }<a name="line.137"></a>
<span class="sourceLineNo">138</span>    }<a name="line.138"></a>
<span class="sourceLineNo">139</span><a name="line.139"></a>
<span class="sourceLineNo">140</span>    private static double adjustExpectedPerformance(long referenceDuration, double referenceBIPS) {<a name="line.140"></a>
<span class="sourceLineNo">141</span>        double currentBIPS = currentBIPS();<a name="line.141"></a>
<span class="sourceLineNo">142</span>        return referenceDuration * (currentBIPS / referenceBIPS);<a name="line.142"></a>
<span class="sourceLineNo">143</span>    }<a name="line.143"></a>
<span class="sourceLineNo">144</span><a name="line.144"></a>
<span class="sourceLineNo">145</span>    private static double adjustExpectedDuration(long referenceDuration, double referenceBIPS) {<a name="line.145"></a>
<span class="sourceLineNo">146</span>        double currentBIPS = currentBIPS();<a name="line.146"></a>
<span class="sourceLineNo">147</span>        System.out.println("currentBIPS=" + currentBIPS + " BIPS");<a name="line.147"></a>
<span class="sourceLineNo">148</span>        return referenceDuration * (referenceBIPS / currentBIPS);<a name="line.148"></a>
<span class="sourceLineNo">149</span>    }<a name="line.149"></a>
<span class="sourceLineNo">150</span>}<a name="line.150"></a>




























































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